BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a mirror surface angle adjusting mechanism which is mounted to a vehicle or the like and adjusts a mirror surface angle of a mirror for rearward vehicle vision.

[0003] 2. Description of the Related Art

[0004] A vehicle or the like is provided with a mirror for rearward vehicle vision. A mirror surface angle adjusting mechanism 50 of the mirror includes, for example, as shown in FIGS. 3 through 5, a mirror holder inner 52 for holding a mirror for rearward vehicle vision (not shown). A hemispherical portion 54 which is formed in a substantially hemispherical shape is formed at the mirror holder inner 52. A circular opening 56 is formed at a center of the hemispherical portion 54.

[0005] A case pivot 58 is placed on the opposite side from the mirror side of the mirror holder inner 52. The case pivot 58 is formed of a case lower 58A and a case upper 58B. The case lower 58A is disposed at a side of the case pivot 58 facing the mirror holder inner 52. The case upper 58B is disposed at a side of the case pivot 58 opposite to the side thereof at which the mirror holder inner 52 is disposed. A convex portion 60 is formed on a whole periphery of the case lower 58A and a concave portion 62 is formed on a whole periphery of the case upper 58B. Due to the convex portion 60 fitting into the concave portion 62, the case lower 58A fits into the case upper 58B on their whole peripheries. As a result, waterproofing within the case pivot 58 is accomplished.

[0006] The case pivot 58 is provided with a pair of rods 64. The respective rods 64 insert into the case lower 58A. The mirror holder inner 52 is held by the tip ends of rods 64. The mirror holder inner 52 can tilt relative to the rods 64.

[0007] A pair of motors (not shown) is provided within the case pivot 58. Each motor has a motor main body and a motor shaft. A shown in FIG. 4, two pairs of motor main body receiving portions 66 are provided at a back surface side of the case lower 58A. Two pairs of motor bearing portions 68 are also provided at the back surface side of the case lower 58A. Each of the pairs of motor main body receiving portions 66 presses the motor main body, and each of the pairs of motor bearing portions 68 presses the motor shaft. In this way, the motors are fixed within the case pivot 58. The motor shafts are connected respectively to the rods 64. The rods 64 slide in their axial direction due to the driving of the motors.

[0008] A pivot portion 70 is formed at a front surface side of the case lower 58A. The pivot portion 70 is formed in a substantially hemispherical shape. A cylindrical pivot shaft 72 is formed upright at a center of the pivot portion 70. The hemispherical portion 54 of the mirror holder inner 52 is fitted into the pivot portion 70 with the pivot shaft 72 being inserted into the opening 56 of the mirror holder inner 52. A self-tapping screw 76 is screwed into the tip end of the pivot shaft 72 with a snap ring 74 being interposed therebetween.

[0009] A support pivot 78 is placed around the pivot shaft 72. The support pivot 78 has a substantially hemispherical support portion 80. The support portion 80 fits into the hemispherical portion 54 of the mirror holder inner 52. A cylindrical pivot cylinder 82 is provided at a center of the support portion 80. The pivot cylinder 82 surrounds the pivot shaft 72. An annular wall 82A is formed at the case pivot 58 side end portion of the pivot cylinder 82. The annular wall 82A fits into the pivot shaft 72.

[0010] A compression coil spring 84 is mounted between the snap ring 74 and the annular wall 82A of the pivot cylinder 82. The compression coil spring 84 applies an urging force to the support pivot 78. For this reason, the hemispherical portion 54 is nipped between the pivot portion 70 and the support portion 80 with the urging force of the compression coil spring 84 being acted. Thus, the mirror holder inner 52 is held between the case pivot 58 and the support pivot 78.

[0011] When the motors are driven and the rods 64 are slid in their axial direction, a tilt force is applied to the mirror holder inner 52. At this time, the hemispherical portion 54 is slid relative to the pivot portion 70 and the support portion 80 such that the mirror holder inner 52 is slid. In this way, a mirror surface angle of the mirror is adjusted.

[0012] However, in such mirror surface angle adjusting mechanism 50, in order to make the case pivot 58 compact, the motors, the convex portion 60 and the concave portion 62 are provided at a portion that the pivot portion 70 is formed. For this reason, the pair of motor main body receiving portions 66, the pair of motor bearing portions 68 and the convex portion 60 are formed at the back surface side of the pivot portion 70, i.e., at the portion opposing the pivot portion 70 on the back surface side of the case lower 58A, as shown in FIG. 4.

[0013] Because the pair of motor main body receiving portion 66, the pair of motor bearing portions 68 and the convex portion 60 are provided at the back surface side of the pivot portion 70, it is impossible to form a circular thinning portion 86 from the back surface side of the pivot portion 70. Therefore, it is difficult to make a thickness of the pivot portion 70 uniform. Specifically, since the pair of motor main body receiving portion 66 and the convex portion 60 are formed, the circular thinning portion 86 cannot be formed at the portion that the pair of motor main body receiving portion 66 and the convex portion 60 are formed. Thus, the thickness of the pivot portion 70 cannot be made uniform. Consequently, as shown in FIG. 4, the thickness of the pivot portion 70 is large at the portion that the pair of motor main body receiving portion 66 and the convex portion 60 are formed (i.e., a portion A shown in FIG. 5). Further, the thickness of the motor bearing portions 68 is decreased because the circular thinning portion 86 is formed. Thus, as shown in FIG. 4, strength of the motor bearing portions 68 may decrease.

[0014] As described above, since it is difficult to make the thickness of the pivot portion 70 uniform, a slight formation error such as a dent is apt to occur at the portion of the pivot portion 70 having a large thickness because of variation of thickness. Thus, there arises a problem in that it is difficult to ensure a precision of a spherical surface of the pivot portion 70. Thus, there arises a problem in that when the hemispherical portion 54 is slid relative to the pivot portion 70 and the support portion 80, when the mirror surface angle of the mirror is being adjusted, sliding noise is generated between the pivot portion 70 and the hemispherical portion 54.

[0015] Moreover, since the pivot portion 70 is formed in a substantially hemispherical shape, a lubricant such as grease or the like cannot be filled sufficiently into the pivot portion 70. Thus, the lubricant in the pivot portion 70 easily runs out. In a case in which the lubricant in the pivot portion 70 runs out, when the hemispherical portion 54 is slid relative to the pivot portion 70 and the support portion 80, when the mirror surface angle of the mirror is being adjusted, the hemispherical portion 54 catches against the pivot portion 70 such that swinging or sticking of the mirror may occur.

SUMMARY OF THE INVENTION

[0016] In view of the above-mentioned, an object of the present invention is to provide a mirror surface angle adjusting mechanism which can ensure a precision of hemispherical surface of pivot portion and can prevent a lack of lubricant in the pivot portion.

[0017] In accordance with a first aspect of the present invention, there is provided a mirror surface angle adjusting mechanism comprising: a mirror retaining member having a hemispherical portion formed in a substantially hemispherical shape; a case member into which the hemispherical portion of the mirror retaining member is fitted and which has a plurality of ribs arranged in a circumferential direction relative to the hemispherical portion, the ribs including surfaces at a side at which the hemispherical portion fits, being substantially complementary to at least a part of the substantially hemispherical shape; and a lock means which nips the hemispherical portion of the mirror retaining member between the surfaces of the ribs and the lock means and which presses the hemispherical portion toward the ribs.

[0018] Further, the plurality of ribs each may have substantially the same thickness as one another. The lock means may comprise resiliently deformable member for pressing the hemispherical portion of the mirror retaining member so as to nip the hemispherical portion between the ribs and the lock means with an elastic force being acted. By tilting the retaining member, a mirror surface angle of the mirror can be adjusted.

[0019] In accordance with the first aspect of the present invention, the pivot portion of the case member has a predetermined number of ribs. The predetermined numbers of ribs are arranged in a circumferential direction relative to the hemispherical portion of the retaining member. Further, the surfaces of the predetermined number of ribs at the hemispherical portion side thereof are formed corresponding to a section of a hemispherical shape. The hemispherical portion is nipped between the predetermined number of ribs and the lock means with the elastic force being acted. Thus, the retaining member is held between the case member and the lock means.

[0020] Consequently, when the hemispherical portion is slid with respect to the predetermined number of ribs and the lock means, the retaining member is tilted such that the mirror surface angle of the mirror held by the retaining member is adjusted.

[0021] Since the predetermined numbers of ribs have substantially the same thickness, generation of partial dent caused by variation of the thickness of the ribs is significantly decreased. Accordingly, the precision of the spherical surface of the predetermined number of ribs which form the pivot portion can be ensured. When the hemispherical portion is slide with respect to the predetermined number of ribs and the lock means such that the mirror surface angle of the mirror is adjusted, it is possible to prevent generation of sliding noise between the predetermined number of ribs and the hemispherical portion.

[0022] Moreover, clearances between the ribs may act as a lubricant pool. Thus, the lubricant can be sufficiently filled into the pivot portion such that a lack of the lubricant in the pivot portion can be prevented. Accordingly, when the hemispherical portion is slid with respect to the predetermined number of ribs and the lock means such that the mirror surface angle of the mirror is adjusted, it is possible to prevent the hemispherical portion being caught by the predetermined number of ribs, swinging or sticking of the mirror.